Generally, a high-tension wire for transferring high-tension power is set over an electric pole placed in outdoor and FIG. 5 shows a conventional telegraph pole in part. In FIG. 5, there is a fixing device 9 which is horizontally installed on an electric pole 10 and a second fixing device 9' under the fixing device 9. The fixing device 9 supports three high-tension wires 11 and the second fixing device 9' is installed with a circuit breaker 12 or a lightning arrester (not shown) which is electrically connected with the high-tension wires 11. The circuit breaker 12 is connected with a transformer 14 placed below thereof so that it may break overvoltage.
Recent times, birds such as magpies and swallows build nests with branches of a tree or pieces of iron wire on electric poles 10 over which high-tension wires 11 are set, especially on the second fixing device 9' that is suitable place to build nests. The pieces of iron wire used for building a nest cause a short circuit by transmitting electricity among the high-tension wires 11 or an interruption of electric power by short circuit.
Accordingly, up to now various devices have been worked out to prevent these accident: a worker removes birds' nests directly, puts a convex cover on the horizontal fixing device in order not to build a nest on an electric pole, or installs shining means by the reflected light of the sun or rotating means such as vane to prevent birds from approaching.
Another device puts a container filled with fluid or emulsion polymer on a fixing device of the electric pole which creates an unpleasant feeling in birds that come around the container, thereby causing them to fly away.
However, birds are used to building a new nest on the same electric pole. Accordingly, there was a problem to repeat removal work that should mobilize lots of manpower and equipments.
Moreover, as time passed, birds build nests again on the electric poles with evading the hinderers installed. Therefore, the fundamental problem can not be solved.